Powdered zinc anode for primary cells



March 28, 1950 A, GLASSNER 2,501,673

' POWDERED ZINC ANODE FOR PRIMARY CELLS Filed Dec. 4, 19215 FIG.2.

INVENTOR. ALVIN GLASSNER BY c Patented Mar. 1950 PWDERED ZINC ANODE FORPRIMARY CELLS Alvin Glassner, Eatontown, N. J., assignor to the UnitedStates of America as represented bythe Secretary of War ApplicationDecember 4, 1945, Serial No. 632,781

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) 2 Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to me ofany royalty thereon.

This invention relates to anodes for primary electric cells of thealkaline dry type, and more particularly to primary cells having ananode of zinc, an alkaline electrolyte and a depolarizing electrodeformed of an oxidizing agent.

, An object of the invention is to provide an improved anode for aprimary dry cell, so that the cell may have increased capacity.

, Other objects and advantages will be appreciated by those skilled inthe art.

. It'has been customary, in making cells operating under the samegeneral system as the cell for which this invention was originated, toconstruct the anode as a roll or spiral of adjacent strips of corrugatedzinc foil and paper, the latter being subsequently saturated with aliquid electrolyte. The roll or spiral form of anode has been used dueto the comparatively large surface area afforded thereby, the currentdensity being thereby diminished, with the consequent advantage ofgreater capacity of the cell under high current drain. A

In the improved cell of my invention, I provide an anode having asurface area many times that afforded by the spiral form, therebyfurther diminishing the current density of the I anode, and furthergreatly improving the capacity of the cell under high current drain. My

invention also enables me to dispense with the y operation ofccrrugating the zinc, thereby simporous. such as asbestos ordiatomaceous earthl or other known porous mineral matter. The partlclesof such non-conducting and electrolyteabsorbent material function asreservoirs of electrolyte, which is fed to the surfaces of the anodicparticles in the event that part of the electrolyte leaks out of theporous anodic metal. The anode of the invention, whether with or withoutthe non-conducting porous particles, may be formed on a web er gauze asa base.

The type of anode disclosed provides a much larger interstitial area incontact with the electrolyte than is afforded by prior types of anodes,whereby the cell employing the improved anode has an increased capacityfor any given size of cell.

The anode described, according to this invention, is arranged in layerswhich alternate with layers of an electrically non-conducting,electrolyte-absorbent material, as paper for example, and suchalternating layers are hereinafter illustrated as being in the form of aroll, but need not necessarily be so, as they may be arranged inparallellayers.

The drawings show the construction of a dry cell embodying theinvention.

In the drawings:

Figure 1 is a central vertical section of the cell;

Figure 2 shows the cell in elevation;

Figure 3 is a plan view of a web or gauze employed in the constructionof the cell; and

Figure 4 is an enlarged side view of the web or gauze to whichcompressed and cohering particles are adherent on both faces.

Referring to the drawings for a more 'detailed description thereof, thenumeral 5 indicates an integral steel container having a base part 6,and an upper part 1 which is of larger diameter than the base part, aledge 8 being thereby formed.

A depolarizing cathode 9 is pressed into the base part 6 and fills thesame, the upper surface of the cathode being substantially ush with theledge 8. The cathode for the type of cell illustrated is of a knowntype, and is a body made by compressing a mixture of mercurio oxide andgraphite, both in comm'inuted form.

Lying on, and pressing against, the cathode 9, is a permeable barrieril), about .003 inch thick, which is disposed in the upper and enlargedpart of the container, andv extends to the inner surface of the same.The outer, marginal portion of the barrier, lies on, and pressesagainst, the ledge 8, thereby functioning asa seal between the cathodeand the anode of the cell to prevent the passage of material from oneelectrode to the other. It will be understood, however, that thebarrier, being permeable to the electrolyte, allows the passage ofcurrent between the elec- Y trodes.

contacting strips or sheets I2 and Il, in lapped or offset relation, thelatter extending below the former and contacting the barrier I0. Thestrip I3 is of electrically non-conducting material. such as paper, andis adapted to absorb electrolyte, as known in the art. This strip may beomitted and the anode roll formed from the porous zinc sheet alone.

The strip I2 is shown in Figure 4 as comprising an open web, or gauzeI4, of which Figure 3 is a plan view. Said web may be of mercerizedcotton, being mercerized to avoid shrinkage. The web is saturated withwater and it is then coated, preferably on both faces, with a mixture I5consisting of zinc particles and particles of electricallynon-conducting, electrolyte-absorbent material such as asbestos,diatomaceous earth or other known porous mineral matter. The particlesof zinc may have an average size of 100-200 mesh, while thenon-conducting particles, which preferably constitute from 5% to 15% ofthe mixture, may have an average size of 250 mesh. The mentionedmixture, applied to the web Il, may be passed between a series of pairsof hot rolls, which work successively at higher pressures, the nal pairof rolls exerting a pressure of 5000 to 8000 pounds per square inch,whereby an integrated strip or sheet is formed.

The mentioned web I4 is desirable as giving strength to the strip orsheet, but is not essential, as a sheet may be formed without it, merelyby compressing the mixture described above. Likewise, the mentionednon-conducting, electrolyte-absorbent matter is desirably incorporatedfor the reason previously stated, but may be omitted, and the sheetformed by compressing the zinc particles alone.

Surrounding the anode, and filling the space between it and the innerwall of the upper part of the container, is an insulating component I1,which rests on, and presses against, the marginal portion of thebarrier. The insulator I1 therefore not only serves to insulate theanode from the inner wall of the upper part of the container, but, byfilling the space mentioned,

and also by pressing on the marginal portion of Y the barrier, functionsto assist in making the barrier an effective seal to prevent themovement of material from each electrode to the other.

A metallic top or closure I9, preferably of zinc, 'is provided for thecell. This top has a centrally depressed area which contacts the uppersurface of the anode body II, while the relatively elevated peripheralmargin ts into the channeled insulating grommet 20. The grommet ispressed onto both sides of the marginal portion of the top I9, to form atight seal in combination with the upper edge of the container, which isturned inwardly and downwardly to exert pressure on the grommet 20 andthe to'p I9, so that the anode body II and the insulator I1, bytransmitted pressure, bear down on the barrier I0, whereby the latterforms an effective seal for the purpose previously mentioned.

The nature of the electrolyte for this type of cell is known, being anaqueous solution of an alkali hydroxide, substantially saturated withzinc oxide when the anode is zinc. For convenience, it is stated herethat the electrolyte may be made by dissolving grams of potassiumhydroxide in grams of water, to which solution 12 grams of zinc oxideare added and dissolved therein. As stated above, the elements of theanode body are electrolyte-absorbent and this body is therefore immersedin the electrolyte until saturated with the same.

What is claimed is:

1. An improved zinc anode for primary cells having an alkalineelectrolyte and a depolarizing electrode formed of an oxidizing agent,said zinc anode comprising an electrolyte-absorbing sheet of a mixtureof cohering particles of powdered zinc and particles of porous,electrically non-conducting mineral material, said sheet formed into aspirally wound body.

2. An improved zinc anode according to claim 1 characterized in thatsaid porous, electrically non-conducting particles comprise a mineralmaterial selected from the group consisting of asbestos and diatomaceousearth.

ALVIN GLASSNER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 413,438 Eggers Oct. 22, 1889546,739 Johnson et al Sept. 24, 1895 2,307,627 Lawson Jan. 5, 19432,422,045 Ruben June 10, 1947 2,463,316 Ruben Mar. 1, 1949 FOREIGNPATENTS Number Country Date 271,496 Great Britain Sept. 29, 1927 862,859France Dec. 3, 1940

1. AN IMPROVED ZINC ANODE FOR PRIMARY CELLS HAVING AN ALKALINEELECTROLYTE AND A DEPOLARIZING ELECTRODE FORMED OF AN OXIDIZING AGENT,SAID ZINC ANODE COMPRISING AN ELECTROLYTE-ABSORBING SHEET OF A MIXTUREOF COHERING PARTICLES OF POWDERED ZINC AND PARTICLES OF POROUS,ELECTRICALLY NON-CONDUCTING MINERAL MATERIAL, SAID SHEET FORMED INTO ASPIRALLY WOUND BODY.